U.S. patent number 8,076,905 [Application Number 12/218,826] was granted by the patent office on 2011-12-13 for battery charging method and device thereof.
This patent grant is currently assigned to Acer Incorporated. Invention is credited to Kuan-Chi Juan, Hui Pin Ko.
United States Patent |
8,076,905 |
Ko , et al. |
December 13, 2011 |
Battery charging method and device thereof
Abstract
A battery charging method and device thereof are disclosed. The
method includes the following steps. First, a charging current is
supplied into a plurality of cell blocks of a battery module for
charging, and the terminal voltages of the cell blocks are
detected, when one of said terminal voltages exceeds a first
threshold, the charging is kept continuously over a first preset
time period. If one of said terminal voltages of said cell blocks
exceeds a second threshold, an over voltage protection is
performed, else the charging current is reduced and the battery
module is charged by the reduced charging current continuously over
a second preset time period and if the cell blocks are determined
that they are fully charged, the charging is stopped, otherwise,
the battery module is charged continuously. Therefore, the battery
charging method and device thereof in accordance with the present
invention can prevent the battery module from being overcharged and
prolong its life.
Inventors: |
Ko; Hui Pin (Taipei Hsien,
TW), Juan; Kuan-Chi (Taipei Hsien, TW) |
Assignee: |
Acer Incorporated (Taipei
Hsien, TW)
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Family
ID: |
40533548 |
Appl.
No.: |
12/218,826 |
Filed: |
July 18, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090096428 A1 |
Apr 16, 2009 |
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Foreign Application Priority Data
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Oct 12, 2007 [TW] |
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96138377 A |
Jan 21, 2008 [TW] |
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97102257 A |
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Current U.S.
Class: |
320/134;
320/160 |
Current CPC
Class: |
H02J
7/0022 (20130101); H02J 7/0091 (20130101); Y02T
10/7055 (20130101); Y02T 10/70 (20130101) |
Current International
Class: |
H01M
10/44 (20060101); H01M 10/46 (20060101) |
Field of
Search: |
;320/107,116,128,130,134,136,160 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tso; Edward
Attorney, Agent or Firm: Hudak, Shunk & Farine Co.
LPA
Claims
What is claimed is:
1. A battery charging method including the steps of: (a) supplying
a charging current into a battery module having a plurality of cell
blocks for charging; (b) detecting the terminal voltages of said
cell blocks; (c) continuously charging over a first preset time
period if one of said terminal voltages exceeds a first threshold;
(c') determining whether or not one of said terminal voltages of
said cell blocks exceeds a second threshold, and performing step
(d) if one of said terminal voltages of said cell blocks exceeds
said second threshold, otherwise performing step (e); (d)
performing an over voltage protection; and (e) determining whether
or not said cell blocks are fully charged, and stopping charging if
said cell blocks are fully charged, otherwise performing step (a)
or step (c').
2. The battery charging method of claim 1, wherein the step (e)
further includes sub-steps of: stopping charging said battery
module over a second preset time period; and determining whether or
not one of said terminal voltages falls below a third threshold,
wherein said cell blocks are determined being not fully charged if
one of said terminal voltages falls below a third threshold,
otherwise, said cell blocks are determined being fully charged.
3. The battery charging method of claim 1, wherein said first
threshold is smaller than the voltage value in which said cell
block is fully charged.
4. The battery charging method of claim 1, wherein the second
threshold is greater than the voltage value in which said cell
block is fully charged.
5. The battery charging method of claim 2, wherein the step (e)
further includes including a sub-step of: continuously charging
over a third preset time period if said cell blocks are determined
being not fully charged.
6. A battery charging method including the steps of: (a) supplying
a charging current into a battery module having a plurality of cell
blocks for charging; (b) detecting the terminal voltages of said
cell blocks; (c) continuously charging over a first preset time
period when one of said terminal voltages exceeds a first
threshold; (c') determining whether or not one of said terminal
voltages of said cell blocks exceeds a second threshold, and
performing step (d) if one of said terminal voltages of said cell
blocks exceeds a second threshold, otherwise, performing step (e);
(d) performing an over voltage protection; (e) reducing the
charging current and continuously supplying reduce charging current
over a second preset time period; and (f) determining whether or
not said cell-blocks are fully charged, and stopping charging if
said cell-blocks are determined being fully charged; otherwise,
performing step (a) or step (c').
7. The battery charging method of claim 6, wherein the step (f)
further includes a sub-step of: determining whether one of the
terminal voltages falls below a third threshold, wherein said cell
blocks are determined being not fully charged if one of the
terminal voltages falls below a third threshold, otherwise, said
cell blocks are determined being fully charged.
8. The battery charging method of claim 6, wherein the first
threshold is smaller than the voltage value in which said cell
blocks are fully charged.
9. The battery charging method of claim 6, wherein the second
threshold is greater than the voltage value in which said cell
blocks are fully charged.
10. The battery charging method of claim 7, wherein the step (f)
further includes a sub-step of: continuously charging over a third
preset time period if said cell blocks are determined being not
fully charged.
11. A battery charging device, applied for a battery module having
a plurality of cell blocks, said battery charging device
comprising: a charging module for supplying a charging current into
said cell blocks; an over voltage protection module for providing
an over voltage protection function to said cell blocks; and a
control module for detecting the terminal voltages of said cell
blocks, when one of said terminal voltages exceeds a first
threshold, said control module continuously supplying said charging
current into said battery module over a first preset time period,
and then determining whether or not one of said terminal voltages
of said cell blocks exceeds a second threshold.
12. The battery charging device of claim 11, wherein said control
module enables said over voltage protection module to provide said
voltage protection function if the control module determines that
one of said terminal voltages of said cell blocks exceeds said
second threshold after said first preset time period.
13. The battery charging device of claim 11, wherein said control
module controls said charging module to reduce said charging
current and continuously supplying said reduced charging current
over a second preset time period if said control module determines
one of terminal voltages of the cell blocks falls below said second
threshold after said first preset time period.
14. The battery charging device of claim 13, wherein said control
module determines whether or not one of said cell blocks falls
below said third threshold after said charging module charges said
battery module over said second preset time period, and said
control module determines that cell blocks are not fully charged if
one of said cell blocks falls below said third threshold,
otherwise, said control module determines that cell blocks are
fully charged.
15. The battery charging device of claim 11, wherein said charging
device further comprises an built-in memory for storing said first
threshold, said second threshold, said third threshold, said first
preset time period and said second preset time period.
16. The battery charging device of claim 11, wherein said control
module comprises a counter to calculate said preset time
periods.
17. The battery charging device of claim 11, wherein said first
threshold is smaller than the voltage value in which said cell
blocks are fully charged.
18. The battery charging device of claim 11, wherein said second
threshold is greater than the voltage value in which said cell
blocks are fully charged.
Description
FIELD OF THE INVENTION
The invention relates a battery charging method and device thereof,
and more particularly to a battery charging method and device
capable of retarding deterioration of the battery.
BACKGROUND OF THE INVENTION
As the technology grows and advances rapidly, the battery becomes
an electrical power source which is not considerably replaceable
and been extensively used for devices as MP3 player, cellular
phone, notebook computer, electric vehicle and the likes.
Therefore, a variety of charging means for battery have been
proposed, such as "Constant Trickle Current Charge", "Constant
Current Charge", "Constant Current Constant Voltage Charge" and
"Two-Step Charging", etc.
Battery aging is known as a very important topic in battery
technology. A deteriorated battery not only causes lower storage
capacity and low usage efficiency, but also creates a significantly
risk due to the overcharging of the cell blocks, since the terminal
voltage difference of normal cell blocks is normally greater than
normal cell blocks during charging operation. FIGS. 1A and 1B
illustrates a schematic view of voltage distribution in accordance
with a battery module having a plurality of normal and deteriorated
cell blocks respectively. In FIG. 1, since all three cell blocks
101 to 103 are normal cell blocks, so the charging voltage 12.6V
are equally supplied to each one of cell blocks 101 to 103, the
terminal voltage of cell blocks 101 to 103 is 4.2V respectively
therefore.
When deterioration that occurs in one of the cell blocks comprised
in battery module 1, for example the cell block 102, the terminal
voltages of cell block 102 will greater than other normal cell
blocks 101 and 103 during charging. As shown in FIG. 1B, the
terminal voltage of deteriorated cell block 102 is 4.3V and
terminal voltages of normal cell block 101 and 103 are 4.15V
respectively. Hence if cell block 102 remains deteriorated, the
terminal voltage of cell block 102 would increase accordingly and
may result in hazardous explosion by cell block 102.
In order to ensure the battery module fully charged, the
conventional charging method typically supplies the charging
voltage exceeding the safety load limit of the battery module,
resulting in deteriorated scenario of the cell blocks after a long
term period. Besides, though the battery module equips both over
voltage protection as well as over current protection mechanisms,
such mechanisms are designed for entire battery module, it is not
able to reduce the risk caused by a single deteriorated cell
block.
In view of the drawbacks of the prior art, the inventor of the
present invention based on years of experience in the related
industry to conduct extensive researches and experiments, and
finally developed a charging method and device in accordance with
the present invention to overcome the drawbacks of the prior
art.
SUMMARY OF THE INVENTION
Therefore, one of objectives of the present invention is to provide
a battery charging method and device thereof to charge battery
module safer and retard deterioration of the battery.
To achieve the foregoing objective, the present invention provides
a battery charging method including the steps of:
(i) supplying a charging current into a battery module having a
plurality of cell blocks for charging;
(ii) detecting the terminal voltages of said cell blocks;
(iii) continuously charging over a first preset time period if one
of said terminal voltages exceeds a first threshold, and then
determining whether or not one of said terminal voltages of the
cell blocks exceeds a second threshold, and performing step (iv) if
one of the terminal voltages of said cell blocks exceeds the second
threshold, otherwise performing step (v);
(iv) performing an over voltage protection; and
(v) determining whether or not said cell blocks are fully charged,
and stopping charging if said cell blocks are fully charged,
otherwise performing step (i).
Besides, the present invention further provides a battery charging
method including the steps of:
(a) supplying a charging current into a battery module having a
plurality of cell blocks for charging;
(b) detecting the terminal voltages of the cell blocks;
(c) continuously charging over a first preset time period when one
of the terminal voltages exceeds a first threshold;
(c') determining whether or not one of said terminal voltages of
said cell blocks exceeds a second threshold, and performing step
(d) if one of said terminal voltages of the cell blocks exceeds
said second threshold, otherwise, performing step (e);
(d) performing an over voltage protection; and
(e) determining whether or not said cell blocks are fully charged,
and stopping charging if said cell blocks are determined being
fully charged, otherwise, performing step (c').
Besides, the present invention further provides a battery charging
method including the steps of:
(A) supplying a charging current into a battery module having a
plurality of cell blocks for charging;
(B) detecting the terminal voltages of the cell blocks;
(C) continuously charging over a first preset time period when one
of said terminal voltages exceeds a first threshold, and
determining whether or not one of the terminal voltages of said
cell blocks exceeds a second threshold, and performing step (D) if
one of the terminal voltages of said cell blocks exceeds a second
threshold, otherwise, performing step (E);
(D) performing an over voltage protection;
(E) reducing the charging current and continuously supplying reduce
charging current over a second preset time period; and
(F) determining whether or not said cell-blocks are fully charged,
and stopping charging if said cell-blocks are determined being
fully charged; otherwise, performing step (A).
Besides, the present invention further provides a battery charging
method including the steps of:
(1) supplying a charging current into a battery module having a
plurality of cell blocks for charging;
(2) detecting the terminal voltages of the cell blocks;
(3) continuously charging over a first preset time period when one
of the terminal voltages exceeds a first threshold, and then
determining whether or not one of said terminal voltages of the
cell blocks exceeds a second threshold, and performing step (4) if
one of the terminal voltages of the cell blocks exceeds a second
threshold, otherwise, performing step (5);
(4) performing an over voltage protection;
(5) reducing the charging current and continuously supplying
reduced charging current over a second preset time period; and
(6) determining whether or not the cell-blocks are fully charged,
and stopping charging if the cell-blocks are determined being fully
charged, otherwise, performing step (3).
Besides, the present invention further provides a battery charging
device, applied for a battery module having a plurality of cell
blocks. The battery charging device comprising a charging module
for supplying a charging current into said cell blocks; an over
voltage protection module for providing an over voltage protection
function to the cell blocks; and a control module for detecting the
terminal voltages of the cell blocks, when one of said terminal
voltages exceeds a first threshold, said control module
continuously supplying the charging current into the battery module
over a first preset time period, and then determining whether or
not one of the terminal voltages of the cell blocks exceeds a
second threshold.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject matter regarded as the invention is particularly
pointed out and distinctly claimed in the concluding portion of the
specification. The invention, both as to device and method of
operation, together with features and advantages thereof may best
be understood by reference to the following detailed description
with the accompanying drawings in which:
FIG. 1A is a schematic view of voltage distribution in accordance
with a battery module having a plurality of normal cell blocks;
FIG. 1B is a schematic view of voltage distribution in accordance
with a battery module having a plurality of deteriorated cell
blocks;
FIG. 2 illustrates a block diagram of an embodiment of the battery
charging device in accordance with the present invention;
FIG. 3 is a schematic waveform diagram of charging voltage and
charging current of the battery charging device in accordance with
the present invention;
FIG. 4 is a flow chart of first embodiment of the battery charging
method in accordance with the present invention;
FIG. 5 is a flow chart of second embodiment of the battery charging
method in accordance with the present invention;
FIG. 6 is a flow chart of third embodiment of the battery charging
method in accordance with the present invention; and
FIG. 7 is a flow chart of forth embodiment of the battery charging
method in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
To make it easier for our examiner to understand the objective of
the invention, its structure innovative features, and performance,
we use embodiments together with the attached drawings for detailed
description, and the use of the same reference symbols in different
drawings indicates similar or identical items.
FIG. 2 illustrates a block diagram of an embodiment of the battery
charging device in accordance with the present invention. As
illustrated, a charging device 20 applied for a battery module 26
having a plurality of cell blocks 261, comprises a charging module
21, an over voltage protection module 22 and a control module 23.
The charging module 21 is for supplying a charging current into the
cell blocks 261, and the over voltage protection module 22 is for
providing an over voltage protection function to the cell blocks
261 of the battery module 26. Preferably, the charging device 20
further can comprise an built-in memory 24 for storing a first
threshold 241, a second threshold 242, a third threshold 243, a
first preset time period 243 and a second preset time period
245.
The control module 23 is operable to detect the terminal voltages
of the cell blocks 261. When one of the detected terminal voltages
exceeds a first threshold 241, the control module 23 allows the
charging module 21 continuously charging the cell blocks 261 over a
first preset time period 243, and then determines whether or not
one of the terminal voltages of the cell blocks 261 exceeds a
second threshold 242, if yes, it indicates that at least one of
cell blocks 261 is deteriorated cell block, thus the control module
23 enables over voltage protection module 22 to perform an over
voltage protection function, otherwise, the control module 23
controls the charging module 21 to reduce the charging current and
continuously supplies the reduced charging current to cell blocks
261 over a second preset time period 245.
For example, the charging current can be reduced by half each time,
and each reduced charging current is used to charge the battery
module 26 for the second preset time period 245.
In this embodiment, the control module 23 further can comprise a
counter 25 for calculating the aforementioned preset time periods.
The control module 23 performs the aforementioned charging
procedure by executing a charging management program 244.
Preferably, the built-in memory 24 can be implemented using a ROM
or a RAM, for storing the first threshold 241, the second threshold
242, the third threshold 243, the first preset time period 244 and
the second preset time period 245. The counter 25 can be
implemented by hardware.
FIG. 3 illustrates a schematic waveform diagram of charging voltage
and charging current of the battery charging device in accordance
with the present invention, which is the decreasing charging
current waveform and voltage waveform when cell blocks 21 shown in
FIG. 2 is charged. The voltage value in which the cell block 21 is
fully charged is defined as 4.2V. In FIG. 3, line 1 is the waveform
when the cell blocks 261 starts being charged. Because of virtual
voltage effect, even the terminal voltage of cell block 261 has
reached 4.2V, it does not indicate that the cell block is full
charged, and the terminal voltage of cell block 261 will decrease
rapidly when the cell blocks 261 is not in use, as shown by Line 2.
In the other word, the terminal voltage of the cell blocks 261 may
drop below 3.6V in short-time use if no charging operation is
applied thereon, namely the battery charge capacity is not fully
utilized, so as to shorten the service of the battery. Hence, the
conventional battery charging method ensures the usage of charge
capacity of cell blocks 261 being fully utilized by using the
charging voltage exceeding the safety load limit. However, using
the conventional overcharging method to charge 4.3V to cell block
261 having safety limit 4.2V without essentially determining the
status of cell blocks 261 would greatly reduce the service life of
battery module 26 and is accelerated to deteriorate cell blocks
261.
As disclosed aforementioned, when control module 23 detects that
the terminal voltages of cell blocks 261 reaches a first threshold
241 (4.18V in this embodiment), the control module 23 allows the
charging module 21 continuously charging the cell blocks 261 over a
first preset time period 243 (t1), then determines whether or not
one of the terminal voltages of cell blocks 261 exceeds a second
threshold 242 (4.22V in this embodiment). If the terminal voltage
of cell block 261 is greater than 4.22V, which means that this cell
block 261 is deteriorated, an aging effect may take place thereon.
Typically, the terminal voltages of deteriorated cell blocks may
increase rapidly rather than normal cell blocks during battery
charging operation, so the condition of exceeding the second
threshold 242 would occur in such a short period of time. If one of
the cell blocks 21 is determined being an abnormal cell block, the
over voltage protection is performed to avoid risks generated by
continuously charging the deteriorated cell blocks. If the terminal
voltages still fall below 4.22V after continuously charging over a
first preset time period 243 (t1), which indicates that the cell
blocks 261 are normal cell blocks, subsequently the control module
23 controls the charging module 21 for reducing the charging
current and continuously charging cell blocks 261 over a second
preset time period 245 (t2).
In this embodiment, the procedure that control module 23 controls
charging module 21 for reducing charging current and continuously
charging the cell blocks 261 over second preset time period 245
(t2) is disclosed below. When control module 23 reduces the
charging current for cell blocks 26, the reduced charging current
is used to charge the cell blocks 261 for a second preset time
period 245 (t2), the input power of control module 21 is thus
reduced so as to decrease the terminal voltages of cell blocks,
that is, to eliminate virtual voltage effect as well as to make
cell blocks 261 chemically react stable inside cell blocks 261.
After the second preset time period 245 (t2), terminal voltages of
the cell blocks are detected again for determining whether one of
the terminal voltages is lower than a third threshold (4.15V in
this embodiment), if yes, which indicates that the cell blocks 261
is not fully charged, the control module 23 will allow the charging
module 21 continuously charging the cell blocks 261.
After determining the battery module having no deteriorated cell
blocks and allowing the charging module 21 to continuously supply a
charging current over a preset second time period 245 (t2), the
control module 23 reduces the charging current of charging module
21 supplied to cell blocks 261, for example, Line 3 is the waveform
curve of amplitude of the charging current, lastly, and determines
again whether or not battery module 26 is fully charged. These
aforementioned steps will be repeated until the cell blocks 261
being fully charged.
If the terminal voltages of cell blocks 261 are greater than a
preset third threshold, which means that the cell blocks 261 are
fully charged, the control module 23 would stop charging module 21
charging cell blocks 261. Preferably, the length of the first
preset interval 253 (t1) ought to be considered to avoid the
terminal voltages of cell block 261 being charged too high that
would reduce its service life, namely, the length of the second
preset interval 245 (t2) also need be considered the safety load
limit of battery module 26 after charged each time, as well as to
prevent the switch device of battery from switching frequently for
charging.
Besides, the control module 23 can also determine whether or not
cell blocks 21 is fully charged by checking the charging current
supplied to cell blocks 261. Please note, it is well known to
determine whether cell blocks 261 is fully charged in the prior
arts, as well as the over charging protection, so that it is not
necessary to explain it in detail here. It is to be understood that
the example of determining whether cell blocks 261 is fully charged
above is not limited to those precise embodiments, and that various
other changes and modifications for determining whether cell blocks
261 is fully charged may be effected therein by one skilled in the
art without departing from the scope or spirit of the
invention.
FIG. 4 illustrates a flow chart of first embodiment of the battery
charging method in accordance with the present invention. The
method includes the following steps. In step 41 a charging current
is supplied into a battery module having a plurality of cell blocks
for charging. In step 42 the terminal voltages of the cell blocks
is detected for determining whether or not one of the terminal
voltages exceeds a first threshold. If no terminal voltage exceeds
a first threshold, then step 41 is proceeded.
If one of the terminal voltages exceeds a first threshold, the
battery module is continuously charging over a first preset time
period in step 43, and then the terminal voltages of cell blocks
are determined whether or not one of the terminal voltages exceeds
a second threshold in step 44. If one of the terminal voltages
exceeds a second threshold, it indicates that one of the cell
blocks is deteriorated, such that the over voltage protection is
performed in step 45 to avoid risks.
If no terminal voltage exceeds the second threshold, the battery
module is stopped charging over a second preset time period in step
46, and then in step 47, the terminal voltages of the cell blocks
are determined whether or not one of the terminal voltages falls
below a third threshold, if yes, step 41 is proceeded, otherwise,
the process ends.
The step 41 is for determining if the battery module is
deteriorated, and the step 46 and 47 are for determining if these
cell blocks are fully charged. It is to be understood that the
means for determining the charging status of cell blocks are not
limited to these two steps, and that various other changes and
modifications may be included in battery charging management method
by one skilled in the art without departing from the scope or
spirit of the invention.
For example, in step 47 the terminal voltages of the cell blocks
are determined whether or not one of the terminal voltages falls
below the third threshold, if yes, it indicates that the cell
blocks are not fully charged, otherwise, the cell blocks are fully
charged.
Please note, in the aforementioned embodiment, detection of the
terminal voltages of cell blocks includes detection of the voltage
difference between two terminals of cell block, or detection of
voltage of the separate terminal and difference of these voltages
is calculated by an additional circuit. Both detecting methods fall
within the scope of the appended claims of the present
invention.
FIG. 5 illustrates a flow chart of second embodiment of the battery
charging method in accordance with the present invention. The
method includes the following steps. In step 51 a charging current
is supplied into a battery module having a plurality of cell blocks
for charging. In step 52 the terminal voltages of the cell blocks
are detected for determining whether one of the terminal voltages
exceeds a first threshold. If no terminal voltage exceeds the first
threshold, the step 51 is proceeded.
If one of terminal voltage exceeds the first threshold, the cell
blocks are continuously charged over a first preset time period in
step 53, and then in step 54, terminal voltages are determined
whether or not one of them exceeds a second threshold, if yes, an
over voltage protection is performed in step 55, in which at least
one cell blocks is determined to be deteriorated, such that the
over voltage protection is performed to avoid risks.
If no terminal voltage exceeds the second threshold, the battery
module is stopped charging over a preset second time period in step
56, and then in step 57, the terminal voltages are determined
whether or not one of them falls below a third threshold, if not,
it indicates that the battery module is fully charged, so charging
can be stopped.
If one of terminal voltages falls below a third threshold, the
battery module is continuously charged over a preset third time
period in step 58, and then the step 54 is proceeded.
The step 51 is for determining if the deteriorated cell block exist
among the cell blocks, and step 56 and 57 are for determining if
these cell blocks are fully charged. It is to be understood that
the means for determining the charging status of cell blocks are
not limited to these two steps, and that various other changes and
modifications may be included in battery charging management method
by one skilled in the art without departing from the scope or
spirit of the invention.
FIG. 6 illustrates a flowchart of third embodiment of the battery
charging method in accordance with the present invention. The
method includes the following steps. In step 61 a charging current
is supplied into a plurality of cell blocks of a battery module for
charging. In step 62 the terminal voltages of the cell blocks are
determined whether or not one of terminal voltages exceeds a first
threshold. If no terminal voltage exceeds a first threshold, then
the step 61 is proceeded.
If one of terminal voltages exceeds the first threshold, the
battery module is continuously charged over a first preset time
period in step 63, and then in step 64 the terminal voltages are
determined whether or not one of them exceeds a second threshold,
for determining if deteriorated cell blocks exist among cell
blocks. If one of terminal voltages exceeds a second threshold, it
indicates that the battery module is determined having deteriorated
cell blocks among normal cell blocks, so an over voltage protection
(OVP) is performed to avoid risks in step 65.
If no terminal voltage exceeds a second threshold, the charging
current is reduced and the reduced charging current is continuously
supplied into the battery module for charging over a preset second
time period in step 66, and then in step 67, the terminal voltages
are determined whether or not one of them falls below a third
threshold, if yes, it indicates that the battery module is not
fully charged so step 61 is proceeded again. If no terminal voltage
falls below the third threshold, it indicates that the battery
module is fully charged and the process can end.
The step 61 is for determining if these cell blocks are
deteriorated. The step 64 is for determining whether or not a
deteriorated cell block exists in a battery module. If one of
terminal voltage is greater than the second preset threshold, it
indicates that a deteriorated cell block exists in a battery
module, so an over voltage protection is performed. The step 66 is
for reducing the charging current to reduce the input power, which
may decrease the increment of terminal voltages of cell blocks,
such that the battery module can be prevented from damaging due to
high voltage pressure, so as to make the terminal voltages of cell
blocks stable, that is, to eliminate virtual voltage effect as well
as to stable the chemical reaction within cell blocks. The step 67
is for determining whether or not battery module is fully charged.
if the terminal voltages of cell blocks fall below a preset third
threshold, it indicates that the battery module is not fully
charged, so again to continuously supply a charging current,
otherwise, the battery module is fully charged.
The step 66 and 67 are for determining whether these cell blocks
are fully charged. It is to be understood that the means for
determining the charging status of cell blocks are not limited to
these two steps, and that various other changes and modifications
may be included in battery charging management method by one
skilled in the art without departing from the scope or spirit of
the invention.
Please note, in the aforementioned embodiment, detection of the
terminal voltages of cell blocks includes detection of the voltage
difference between two terminals of cell block, or detection of
voltage of the separate terminal and difference of these voltages
is calculated by an additional circuit. Both detecting methods fall
within the scope of the appended claims of the present invention.
The means of adjusting the charging current may adopt the control
module to control the charging module for adjusting charging
current, it is to be understood that the means for adjusting the
charging current are not limited thereto, and that various other
changes and modifications may be included by one skilled in the art
without departing from the scope or spirit of the invention.
Please note, in the aforementioned embodiment of the battery
charging device, the voltage detection is conducted at terminals of
each individual cell block, but is not limited thereto. Namely, by
grouping cell blocks, the control module within battery charging
device may detect the terminal voltages of the cell blocks, if the
terminal voltages are greater than the second threshold, the
grouped cell blocks within the cell blocks are determined as
deteriorated cell blocks.
FIG. 7 illustrates a flow chart of another embodiment of the
battery charging method in accordance with the present invention.
The method includes the following steps. In step 71, a charging
current is supplied into a battery module having a plurality of
cell blocks for charging, and the terminal voltages of the cell
blocks are detected and determined whether one of the terminal
voltages exceeds a first threshold in step 72, if not, step 71 is
performed and a charging current is supplied continuously for
charging the battery module.
If one of the terminal voltages exceeds a first threshold, the
battery module is continuously charged over a first preset time
period in step 73, and then the terminal voltages are determined
whether one of them exceeds a second threshold in step 74. If one
of them exceeds the second threshold, it indicates that the
deteriorated cell blocks exist among normal cell blocks, so the
over voltage protection (OVP) is performed to avoid risks in step
75.
If no terminal voltage exceeds the second threshold, the charging
current is reduced and the reduced charging current is supplied
continuously to charge the battery module over a preset second time
period in step 76, and then the terminal voltages are determined
whether or not one of the them falls below a third threshold in
step 77, if not, it indicates that the battery module is fully
charged, so the process ends.
If one of them falls below the third threshold, it indicates that
the battery module is not fully charged, so in step 78 the battery
is continuously charged over the preset third time period, and the
step 74 is performed again.
The step 71 is for determining whether or not these cell blocks are
deteriorated, the step 74 is for determining whether or not there
is deteriorated cell blocks in a battery module. The step 76 is for
reducing the charging current to eliminate virtual voltage effect
as well as to stable the chemical reaction within cell blocks. Step
77 is for determining if battery module is fully charged, the
battery module is not fully charged if the terminal voltages of
cell blocks fall below the preset third threshold, otherwise, it is
fully charged.
The step 76 and 77 are for determining if these cell blocks are
fully charged. It is to be understood that the means for
determining the charging status of cell blocks are not limited to
these two steps, and that various other changes and modifications
may be included in battery charging management method by one
skilled in the art without departing from the scope or spirit of
the invention.
While the present invention has been described with reference to
the preferred embodiments, it is intended that the invention be not
limited by any of the details of the description therein but
includes all the embodiments which fall within the scope of the
appended claims.
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